Woodcock, N. H. and Dickson, J. A. D. and Tarasewicz, J. P. T. (2007) Transient permeability and reseal hardening in fault zones: evidence from dilation breccia textures. Special Publication of the Geological Society of London, 270. pp. 43-54. DOI 10.1144/GSL.SP.2007.270.01.03Full text not available from this repository.
t is well established that earthquake faulting can create permeability along a fault zone in high competence rocks - by mismatch of the fault walls and by secondary fracture in a surrounding damage zone - and that this permeability is created repeatedly during successive earthquake cycles. Less well proven is that such permeability is transient, being episodically reduced by precipitation of cements in the fracture porosity. The textures of carbonate dilation breccias, formed at around 1.7 km depth on the Dent Fault zone (NW England), lend support to this economically important concept of transient fracture permeability. The key observation is that many breccias reflect only a single episode of brecciation and reseal. A generally applicable explanation of such single-phase breccias is that they were resealed in the interval between major earthquakes, that this reseal made the breccia stronger that the intact rock, and that subsequent brecciation in the same rock volume was inhibited. This reseal-hardening model implies that transient permeability in fault zones may last no longer than the recurrence times of large earthquakes, and that the permeability conduits will change position in the damage zone with time, unless focused at a major fault jog or termination.
|Additional Information:||Part III|
|Uncontrolled Keywords:||2007 AREP; Part III; IA49; IA53; 2007 P|
|Subjects:||02 - Geodynamics, Geophysics and Tectonics|
|Divisions:||02 - Geodynamics, Geophysics and Tectonics
06 - Part-III Projects
|Journal or Publication Title:||Special Publication of the Geological Society of London|
|Page Range:||pp. 43-54|
|Depositing User:||Sarah Humbert|
|Date Deposited:||16 Feb 2009 13:04|
|Last Modified:||09 Jun 2014 16:22|
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